Index: src/OFURL.m
==================================================================
--- src/OFURL.m
+++ src/OFURL.m
@@ -16,11 +16,10 @@
 
 #include "config.h"
 
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
 
 #import "OFURL.h"
 #import "OFString.h"
 #import "OFArray.h"
 #import "OFXMLElement.h"
@@ -135,11 +134,11 @@
 			if ([_scheme isEqual: @"http"])
 				_port = 80;
 			else if ([_scheme isEqual: @"https"])
 				_port = 443;
 			else
-				assert(0);
+				OF_ENSURE(0);
 		}
 
 		if ((UTF8String = tmp) != NULL) {
 			if ((tmp = strchr(UTF8String, '#')) != NULL) {
 				*tmp = '\0';

Index: src/macros.h
==================================================================
--- src/macros.h
+++ src/macros.h
@@ -110,10 +110,19 @@
 	if (!(cond)) {							\
 		fprintf(stderr, "Failed to ensure condition in "	\
 		    __FILE__ ":%d:\n" #cond "\n", __LINE__);		\
 		abort();						\
 	}
+
+#if __STDC_VERSION__ >= 201112L
+# /* C11 compiler, but old libc */
+# ifndef static_assert
+#  define static_assert _Static_assert
+# endif
+#else
+# define static_assert assert
+#endif
 
 #if !defined(_WIN32) && !defined(__DJGPP__)
 # define OF_PATH_DELIMITER '/'
 # define OF_PATH_DELIMITER_STRING @"/"
 # define OF_IS_PATH_DELIMITER(c) (c == '/')